The present invention relates to a process for preparing a powdered oil/fat and particularly, to the same which comprises spray-drying an O/W emulsion containing a partially hydrolyzed soybean protein as an emulsifier and also as a coating substance.
Powdered fats are used as materials of cake mix, doughnut mix, instant food and the like and are recently in great demand. Powdered fats have been prepared by pulverizing a fat having a high melting point at low temperature or by mixing an oil/fat with substances such as modified starch or cellulose. Such processes, however, have some disadvantages. In the former process a highly hydrogenated oil having a melting point of 60.degree.-70.degree. C. must be employed for the convenience of pulverizing, and the powdery product thus obtained is unsatisfactory for use in cake mix and the like because of it being difficult to melt in mouth. In the latter process, the oil/fat bleeds at its high content and therefore, a powdered oil/fat composition having a high oil/fat content cannot be obtained.
In order to overcome the above disadvantages, there has been proposed a process for the preparation of a powdered oil/fat by forming an O/W emulsion with use of an emulsifier, for example sugar esters, proteins such as casein or gelatin, or starches and spray-drying the O/W emulsion (ref. U.S. Pat. Nos. 2,913,342 and 3,393,075). In this process, the powdered fats which are coated with the above-mentioned emulsifier are not in contact with air and therefore, can be stored with good quality for a long time. Also, this product is free-flowing without bleeding of an oil/fat, so that it can be mixed with food materials under dry condition. However, since emulsions using casein or gelatin have a high viscosity in general, the water content should be elevated to the degree of 70-90% by weight to decrease the viscosity in the spray-drying. Accordingly, in this process a great amount of water should be evaporated on spray-drying in order to obtain a powdered oil/fat and accordingly, energy costs are enormous.